Tank seal with finger



7, 1968 K. D. CHALLENGER ET AL TANK SEAL WITH FINGER 2 Sheets-SheetFiled Feb. 9, i966 I N VEN TORS ATTORNEY 1968 K. D. CHALLENGER ET L TANKSEAL WITH FINGER 2 Sheets-Sheet 2 Filed Feb. 9, 1966 /(e/7/7ez/7 .0.Cfiaflenger J7me: h Meir/en INVENTORS ATTORNEY United States Patent3,398,851 TANK SEAL WITH FINGER Kenneth D. Challenger and James H.McBrien, Houston,

Tex., assignors to Helmerich & Payne, Inc., a corporation of DelawareFiled Feb. 9, 1966, Ser. No. 526,293 6 Claims. (Cl. 220-26) ABSTRACT OFTHE DISCLOSURE A secondary tank seal for a floating roof, the seal beingflexible and joined to the flange of a movable shoe. One end of theflexible seal rides along the tank wall, and carries spring memberswhich resiliently carry the seal over obstacles.

This invention generally concerns bulk storage tanks utilized to storepetroleum products or the like, such tanks oftentimes having floatingroofs or covers that raise with or float upon the fluid surface withinthe tank.

More particularly, this invention concerns an improved means foreffecting a seal between the interior vertical wall of the tank and theperipheral edge of the roof or cover, and constitutes an improvementover presently pending application Ser. No. 445,919.

A major problem encountered in such floating-cover tanks, is theeffecting of a seal between the cover and the inner periphery of thestorage vessel, said cover necessarily having the smaller diameter inthat it vertically moves within the confines of the vessel. Normallyprimary seal means have been provided which have included guide shoesattached to the cover with aflexible sheet joining the two, barringpassage of fluids therebetween. Secondary seal means have been utilizedto limit the passage of water downwardly through any space existingbetween the movable shoe and the interior vessel wall. Such a secondaryseal is described in said earlier mentioned application. However, it hasbeen found that such secondary seal means have tended to collect waterin any space occurring between the vessel wall and any upwardlyextending surface of the secondary seal, such water passing downwar dlyinto the petroleum products between adjacent joints of the seal.

The secondary seal envisaged herein Would include a flexiblesubstantially crescent shaped member, attached to the movable shoe atone end, and having a sealing lip at the other end. A plurality of guidemeans are spaced around the edge of said member and, by extendingoutwardly thereof, tend to guide the sealing lip over rough spotsoccurring on the inner surface of the vessel wall. Such rough spots maybe welds which tend to cause the secondary seal to become doubled upwith resulting breakage of the seal and disengaging of the sealingmember with a stiffening device provided thereto.

Thus, this invention has as its purpose the provision of a sealing meanscapable of preventing the flow of fluids into the inner cavity of astorage container.

A further object is the provision of means for guiding a sealing deviceover rough spots occurring on a container wall.

Yet another object is the provision of sealing means which may beexpeditiously assembled and disassembled.

These and still other objects and capabilities should become apparent onconsidering the following appended description and drawings, in which:

FIGURE 1 is a partial perspective of the floating roof tank, showing oneembodiment of the seal-glide;

FIGURE 2 is a cross section through the secondary seal showing oneembodiment of the seal-guide;

FIGURE 3 is a cross section similar to FIGURE 2,

"ice

depicting the secondary seal aflixed to the movable shoe, and having astiffening member inserted in the seal;

FIGURE 4 is a perspective of an embodiment of the stiffening member;

FIGURE 5 is a cross section similar to FIGURE 3 showing a secondembodiment of the seal-guide,

FIGURE 6 is a perspective of a seal-guide s1m11ar to that of FIGURE 5;

FIGURE 7 is a cross section similar to FIGURE 2 showing a furtherembodiment of the seal-guide, and

FIGURE 8 is a perspective of yet another embodiment of the seal-guide.

Looking first at FIGURE 1, a portion of an open-ended storage tank isgenerally shown by numeral 10, and mcludes upstanding wall 11.

Associated with the storage tank is a flo'ati ng roof which is indicatedby the numeral 20. This roof is designed to float upon the upper surfaceof the fluid contained within tank 10; The roof includes cover portion21, bottom 22, these two members being connected or joined by plate 23.The space intermediate members 21, 22 and 23 may be subdivided bybulkheads such as 24.

A primary seal between the floating roof and wall 11 of tank 10 may beeffected by vertically sh-dable shoes 30 which are associated with thefloating roof by means of the hanger and balance structure generallyindicated as 31, this latter structure being generally known, and notforming a part of this invention. A continuous flexible sheet material32, would be secured to the roof and to the shoe, as at 33 and 34,respectively. Of course, grounding straps 35 may interconnect the roofand the primary seal. The upper edge of shoe structure 30 s shown tohave an inturned flange 36, said flange coactmg w th the secondary sealof this invention in a manner hereinafter described.

Moving now to FIGURES 2 and 3, one embodiment of the secondary sealcomprising the cr1t1cal element of this invention is shown, andillustrated generally by the numeral 40. Such a seal, while flexible, isshown to have a generally crescent shape, and includes a slot 41 at itslower end. This slot is utilized to envelop and clamp around inturnedlip or flange of shoe 30 when the secondary seal IS affixed thereto.Such a clamping may be enhanced by means of insert 42 being positionedwithin cutout 43 which extends peripherally around seal 40 toward itslower end. Of course, after insertion of insert 42, addltion-al rigiditymay be provided by cementing it in place.

Central body portion 44 of seal 40, is relatlvely thin and flexible byvirtue of wing-shaped cutaway portion which create down-turned lugportions 45, 46, which 1n turn define grooves 47, 48, respectively.Insertable withm said cut-away portion is stiffening member 70, seeFIGURES 3 and 4 especially. This member, while somewhat resilient, isless so than the material making up secondary seal 40. Further, member70 may have an initial length somewhat greater than that between grooves47, 48 so that on insertion therein, said stiffening member may bulge asshown in FIGURE 3. A plurality of such stiffening members 70 may beannularly spaced around the inner periphery of secondary seal 40', whichseal forms a substantially continuous belt around the inside surface ofvessel wall 11. Stiffening member 70 is shown to have oppositelypositioned lips 71, 72, which lips fit snugly within grooves 47, 48 ofseal 40. This coaction of lip-in-groove allows the stiffening member tobe firmly placed.

The upper surface of secondary seal 40 defines a sealing lip 49, whichlip slides along the inside surface of vessel wall '11, and mayyieldingly pass over rough places existing in said wall. However,occasional structural features such as welds 12 or certain defects inWall 11 may exist which impede passage thereover, especially on anupward tlip of the secondary seal. This may cause severe bending of thesecondary seal with resulting dislocation of the stifiening member 70and even a loss of the sealing effect. Therefore, this inventioncontemplates the use of a guide means which-will, in effect, permit thepassage of the sealing lip 49 over such danger areas. One embodiment ofsuch a guide is shown in FIGURES 2 and 3, and comprises a plurality ofspaced spring-like structures 80. Each of said springs may have itsshank 81 imbedded in and/ or aflixed, as by cementing, a recess providedin secondary seal 40. The head 82 may be bent so as to present a curvedsurface Which may normally pass closely adjacent the vessel wall 11 inadvance of sealing lip 49 during its upward journey. Thus, on sealinglip '49 encountering a feature such as weld 12, sealing lip 49 will tendto be restrained and the secondary seal will bend. At this time, guide80 will be pressed against wall 11 and inasmuch as guide 80 issufficiently less resilient than seal 40 it therefore presents a greaterforce of resistance to any tendency of seal 40 to be bent and in effectpushes lip 49 radially inward out of the path of the impediment until itpasses same and can return to contact the vessel wall.

A second embodiment of the guide means of this invention is shown inFIGURES and 6 and represented generally by 80a. This guide also includesa shank 81a, which passes through a recess 8311 that passes through seal40 from a position near sealing lip 49 to exit in the area defined bygroove 47. Spaced inwardly from end 8 40 of shank 81a, is a cross-pieceor support 85a, which is securely affixed to shank 81a, and not onlyincreases the rigidity of the guide, but permits it to be securelypositioned with respect to seal 40, provides ease of assembly byinserting head portion 82a, through aperture 83a of the seal untilcross-piece 85a reaches the upward limit of groove 47 and resists anytendency of the guide to twist or turn on encountering any barrier. Thecross-piece may be positioned outwardly of the stiffening member 70within space 73, as shown in FIGURE 5, or, their respective positionsmay be reversed by placing opposite ends of the cross-piece 85aintermediate lip 71 of stiffener 70 and aperture 83a. In either case,both the stiffening member and the guide may be securely positioned. Itmay be desirable, after assembly to cement, or otherwise unify thejuncture of the stiffening lip, such as 71, cross-piece a and lug, suchas 45. This latter embodiment, while functioning in the same manner asthat shown in FIGURES 2 and 3 provides the added benefit of ease ofinserting the head through the seal, and of more securely unifying theguide to the seal preventing rotation or twisting of the guide withrespect to the seal.

FIGURE 6 includes a loop or finger piece 84a facilitating ease ofinsertion and removal of the guide into and from aperture 83a.

In the further embodiment of FIGURE 7, cross-piece 85b is placed outsideand adjacent the guide rather than within groove 47. This not onlypermits ease of assembly, but also inasmuch as the greatest force: isexerted against the seal during the upward journey, this configurationresists any tendency to force the guide shank back through the secondaryseal body.

In the embodiment of FIGURE 8, struts 90 are provided to opposite endsof cross-piece 850 to further resist any tendency to turn or twist and'a bent end 91 is provided permitting ease of inserting the head throughaperture 83a.

At this point it should be noted that a plurality of seal guides arespaced around the periphery of the secondary seal, each of said guidesindependently functioning. Thus, if damage occurs to one or more of suchguides, the remaining guides may continue to function without deterringthe overall sealing effect.

While only limited embodiments of this invention have been described, itshould be apparent that numerous modifications might be possible by oneskilled in the art Without departing from the spirit of this invention,the scope of which is only intended to be limited by the followingappended claims.

What is claimed is:

1. An improved secondary seal for use with a floating roof in a storagetank, the roof being of the type having a primary seal shoe verticallyslidable along the tank Wall, the improved seal comprising:

a flexible annular body portion, one edge of which is joined to saidshoe, and the opposite edge of which forms a wall engaging portion; and

guide means fixed to said body portion adjacent said wall engagingportion and extending axially upward therefrom so as to guide said sealover obstacles present in said tank wall, said guide means compris' inga plurality of elongated spring elements each having one end extendingthrough an aperture provided in said body portion adjacent said wallengaging portion.

2. The device of claim 1 wherein said body portion includes a recess inits radially inward side, and said spring includes a cross barpositioned within said body portion recess for resisting slippage ofsaid spring relative to said body portion.

3. A secondary seal for use with a floating roof and movable primaryseal shoe arrangement in a storage vessel, the seal including:

a flexible annular member having a generally crescent shaped radialcross section;

thickened portions adjacent the upper and lower edges of said annularmember;

grooves provided in each of said thickened portions,

said grooves generally facing each other;

one of said thickened portions being clamped about a radially inturnedlip of said shoe;

the other of said thickened portions including a wallengaging sealinglip;

stiffener means having opposite edges which are inserted within saidgrooves; and

guiding means joined to said annular member adjacent said upper edge andextending axially outward therefrom adapted to guide said seal overobstacles in the Wall of said storage vessel, said guiding meanscomprising a plurality of elongated springs each having one end embeddedin said annular member.

4. The seal of claim 3 and including passageways through said upperthickened portion and communicating with said upper groove, a portion ofeach of said elongated spring guiding means being inserted within saidpassageway.

5. The seal of claim 4 wherein said guiding means includes a cross barwithin the upper of said grooves for re- Sisting slippage of saidguiding means relative to said annular member.

6. The seal of claim 4 wherein said guiding means includes graspingmeans at one end for facilitating ease of inserting and removing saidguiding means into and from said passageway.

References Cited UNITED STATES PATENTS 2,180,587 11/1939 Hammeren 220-262,354,629 7/ 1944 Wiggins 220-26 3,167,206 1/1965 Nelson 22026 3,261,4967/1966 Joor 220-26 3,275,183 9/ 1966 Challenger 22026 FOREIGN PATENTS1,196,283 5/1959 France. 1,024,434 2/ 1958 Germany.

THERON E. CONDON, Primary Examiner. JAMES R. GARRETT, AssistantExaminer.

